Detection of Melamine in Powdered Milk Using Surface-Enhanced Raman Scattering with No Pretreatment

Abstract

We detected a trace amount of melamine in powdered milk using surface enhanced Raman scattering (SERS) on gold surfaces at an excitation wavelength of 632.8 nm. A detection limit of ∼100 ppm (μg/g) melamine in milk was attained within a few minutes by the gold nanoparticle substrate from chemical reduction; whereas, better sensitivity, as low as ∼200 ppb (ng/g), was achieved by the roughened gold substrate. Our method has the advantage of fast and sensitive detection of melamine in powdered milk without pre-treating the samples.